There are times when I cannot get a decent signal on my radio - even though I am accessing very strong, local stations. Well, today, I noticed the problem is substantially worse when I turn my fog lights on.

I do have some modifications on my fogs:
fog's always on (bypass wire added to the top of the fuse box)
HID's

Just thought it was odd. Not really looking for a solution - I generall use my MP3 or Pandora (awesome). If I'm listening to the radio, I can just shut off my fogs.

Could it be possible I am not grounded correctly? Or is it because I am grounded that its causing the problem? Those HID's use a lot of juice.

I spoke with some people a lot farther up the geek pole than myself. And considering that I can have all four of my HID's on with no radio interference, and the fact that the HID's emit EM radiation at very high frequencies it is very unlikely that the lights, operating normally, are causing any problems. It is most likely that there is a grounding issue somewhere in the electrical system. Or one of the wires coming out of the HID ballast, very high voltage(lots of EM radiation), is too close to a wire that is directly connected to the radio or antenna. So, if its really bothering you start tracing the wires. Hope some of this was helpful to someone.

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Great work, detective! Some of that would be over my head but I get the gist of it. My HID headlights have no effect on the radio reception. So it has to be the grounding on the fogs. This weekend, I'll climb under there and check the wires. I'll also try moving some wires around to see if something is just too close and causing the interference.

I'm also getting a new factory radio next week because the volume dial sporadically works - a well-reported problem.

Thanks again and I'll be sure to post any findings during my investigations. I'm not going to start ripping apart my electrical system because the problem is minimal. But its worth a quick look.

They definitely don't have an effect on my iheart radio app that I play on my Droid phone. Just hook it to my aux port and I'm set. Reception is crystal clear and never cuts out.

True HID light bulbs do not have filaments. It is an arc going through a gas (fluorescent type lighting)... Depending on frequency (brightness) there are always stray radio waves. Alot of HID fogs and headlights are not always true HID. If there is a filament the are not HID but are called HID because of High light discharge.

"Fake" HIDs and one that run on a lower/higher frequency than the radio are not going to interfere with the radio...

Being a service engineer working on imaging equipment, RF interference is an ongoing battle

True HID light bulbs do not have filaments. It is an arc going through a gas (fluorescent type lighting)... Depending on frequency (brightness) there are always stray radio waves. Alot of HID fogs and headlights are not always true HID. If there is a filament the are not HID but are called HID because of High light discharge.

"Fake" HIDs and one that run on a lower/higher frequency than the radio are not going to interfere with the radio...

Being a service engineer working on imaging equipment, RF interference is an ongoing battle

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So as I understand, my HID's were ''fake'' if they were causing interferences?

HIDs are the cause. They do it on my Taco with my Morimoto retrofits. Did it on my 07 Civic Si sedan with retrofits. Did it on my daughters Altima. This is a known issue with aftermarket HID ballasts. Factory HIDs are properly shielded to avoid this.

It would seem to me that the very high voltage spikes created by an HID ballast would introduce a lot of noise into the electrical system of the car thus affecting the operation of the radio and any other audio equipment. It can't be good for the car.

Also, just think about the hum and static you get sometimes when driving underneath power lines. This is only 60hz, nowhere near the frequencies of a radio.

It would seem to me that the very high voltage spikes created by an HID ballast would introduce a lot of noise into the electrical system of the car thus affecting the operation of the radio and any other audio equipment. It can't be good for the car.

Also, just think about the hum and static you get sometimes when driving underneath power lines. This is only 60hz, nowhere near the frequencies of a radio.

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The ballast is just a pulsing step up transformer. It does not hurt the electronics in the car. It is not interfering with anything. It just emits waves that the antena picks up. It's like have your own personal radio station that over powers any other station because it's so close to you.

The reason you can here power lines is because 60Hz is audible. You can not hear the higher frequency of HIDs but that does not mean it will harm anything.

Benefits I have at my job allow me to see RF. Ballasts like fluerecent lighting, cannot be used in an MRI room. They release a ton of "noise" which will corrupt an image... Just like it would corrupt a radio signal if at the same signal of radio waves. It will not harm any other electronics.

Another way to put it.... The noise from the ballast isn't hurting the radio. The radio is just recieving those waves and playing the sound through your speakers because, to the radio, that is the station

If that is true, then why am I not receiving any interference with all four lights on? Your radio is not capable of picking up the freqencies that the HID's are emmitting. The only possibility, as far as interference goes, is that the EM output of the HID's is disrupting/over powering the incoming Radio waves which are relatively weak, especially as you get farther from the Radio stations antenna. But again, if this was the case then everyone with HID's would be experiencing the radio reception problem. Therefore, it is a problem with the grounding/wiring of the electrical/radio system.
Also, power lines disrupt the incoming radio WAVES themselves, the static that you might hear while driving near them is not your radio picking up the power signal and playing it through your speakers.

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What frequency is your ballast producing? Your car radio can pick up alot more than you would think... the "range" of FM is 87.5-108 Mhz. A CB is only 27Mhz and my radio picks that up when i use it and it is out of the "range".

Most people with HIDs have the reception problem. There are a few companies that have "smart RF Ballasts" which are shielded.

A dirty ground is possible but i dont think its likely. to avoid a dirty ground run the ground of the HIDs directly to the battery so if there is power from the ballast "dirtying" the ground, grounding to the source will clean the rest of the ground plain.